Epidemiology is the study of disease or injury in a population – the basic science of public health. Epidemiologists observe, analyze, and report disease, injury, and exposure occurrences in terms of time, place and person.  They identify a disease as it occurs, then use statistics, research and demographics (ethnicity, race and age) to track it as it moves through a population. They also work to develop methods that prevent or control the spread of disease. Hospital standards and guidelines, particularly in the area of infection control, are often developed by Epidemiologists.

Areas of Specialization
Epidemiologists may specialize in clinical health or in infectious diseases such as vaccine-preventable conditions. They may also specialize in chronic illness such as heart diseases or diabetes, or injury related to specific environments or occupations.

Work Environment
Epidemiologists focus either on research or clinical areas. Research Epidemiologists work at college and universities, public health schools, medical schools, and research and development services firms. Clinical Epidemiologists usually work as hospital consultants.  They also work for universities, private research organizations, global, federal, state and local health departments, major health organizations and large medical corporations.